1. Field of the Invention
The invention relates to an apparatus for de-molding injection molded parts, more specifically, to an injection mold which requires lifters to de-mold the part, has a part cavity that is shallower than the lifter cavity detail depth, requires a controlled ejection due to the part geometry (i.e.: part texture or cavity depth), or has limited space in the ejection system. The invention also relates to a method for ejecting a part having an embedded ejector pin.
2. Description of the Related Art
It is prior-art practice, for example, in the case of injection molds, which use lifters to create desired part features, to use embedded ejector pins to hold a molded part stationary in the lifter de-molding axis. The embedded ejector pin allows the molded part to separate from the lifter. This practice has the disadvantage that the molded part is stuck to the embedded pin at the end of the ejection cycle. A molded part that is not ejected is very disadvantageous because it can lead to a disruption of the cycle, defective part(s) when the injection mold closes on the non-ejected part, and thus a lower productivity.
In order to deal with this problem several solutions have been proposed in the prior art. One solution is to use an air blow-off to blow the part off of the embedded ejector pin. This solution has the disadvantages that there is no control of the part when it is blown off and that air blow-offs generate dirt in the injection mold. Another solution is the use of a robot to remove the parts. This solution has the disadvantages of a large capital expense, longer cycle times, and additional maintenance costs. A third solution is to have an operator manually remove the parts. This solution has the disadvantages of inconsistent cycle times, longer cycle times, and additional labor costs.
Accordingly, prior art ejector systems have the disadvantages that they do not provide a satisfactory solution for removing an embedded ejector pin from a molded part.